# subatomic paricles practice

```Protons, Neutrons, and Electrons Practice
Worksheet
Fill in the blanks in the following worksheet. Please keep in mind that the isotope
represented by each space may NOT be the most common isotope or the one
closest in atomic mass to the value on the periodic table.
Atomic
symbol
Atomic
number
Protons
B
Neutrons Electrons
Atomic
mass
6
11
24
31
37
39
29
89
35
43
100
207
Pb
102
89
Mo
70
225
53
81
100
206
159
No
Yb
261
172
106
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159
Finding Protons, Neutrons, and Electrons of Elements
One of the things students frequently have problems with is determining
how many protons, neutrons, and electrons an element has, based only on some
sparse information given to you on the periodic table or in a problem. This review
will give you everything you need to figure it out. First, let's examine one of the
entries in the periodic table:
This is what the entry for helium is on a normal periodic table. The atomic number is
found at the top, and is equal to the number of protons that an element has. The
reason that all atoms of the element have the same number of protons is that the
number of protons determines what element is present - if there were a different
number of protons, you would have a different element. For neutral atoms, the atomic
number is also equal to the number of electrons present because the number of
electrons equals the number of protons in neutral atoms.
The atomic symbol is different for every element. As you might guess, the atomic
symbol and atomic number are very closely related to one another. After all, any
element that has the atomic number &quot;2&quot; will have the atomic symbol &quot;He&quot;. As a result,
if you don't know the atomic number of an element, you can look up the atomic symbol
on the periodic table to find it. As a result, you can determine the number of protons an
element has from the atomic symbol if you have a periodic table handy. The atomic
mass is also different for every element, and also for isotopes of the same element. The
atomic mass is equal to the number of protons that an element has plus the number of
neutrons that an element has. This is because protons have a mass of approximately 1
amu (atomic mass unit) and neutrons have a mass of approximately 1 amu. Electrons
don't count in this calculation, because their mass is small enough that it can usually be
ignored.



Atomic number = number of protons (which, for neutral atoms, is equal to the
number of electrons).
Atomic symbol allows us to find the atomic number because you can just look it
up on the periodic table.
Atomic mass = number of protons + number of neutrons.
http://www.chemfiesta.com
Solutions for the Protons, Neutrons, and Electrons Practice Worksheet:
Atomic
symbol
Atomic
number
Protons
B
Na
Ga
Y
Cu
Tc
Pb
Yb
Ac
Mo
Tl
Fm
No
Yb
Sg
5
11
31
39
29
43
82
70
89
42
81
100
102
70
106
5
11
31
39
29
43
82
70
89
42
81
100
102
70
106
http://www.chemfiesta.com
Neutrons Electrons
6
13
37
50
35
57
125
102
136
53
125
159
159
101
159
5
11
31
39
29
43
82
70
89
42
81
100
102
70
106
Atomic
mass
11
24
68
89
64
100
207
172
225
95
206
259
261
172
265
```